Beaks and Bills
There are beaks and bills, the most obvious and probably the most important adaptation a bird has. There is no difference between beaks and bills. the word "beak" comes from the Old French bec, meaning "mouth"; "bill" comes from Old English bill "bird's beak," related to bill, a poetic word for a kind of sword (especially one with a hooked blade).
Bills are one of the defining characteristics of a bird. They are of course handy for human observers to identify the bird, but most importantly they have a lot to do with defining the bird's lifestyle.
Understanding the bill shape a bird has can be a very useful way to identify the bird type. If you consider that there are broadly only a handful of different kinds of food out there – seeds, nuts and grains, insects and crustaceans, fruit, nectar, mammals – then you can soon pair up that bird’s diet with the shape of its beak. Long, thin bills are for probing, heavy downcurved birds are for tearing, and spear-shaped bills are essential to catching fish, for example.
Many birds depend on insects as their main food source, so their beaks complement their hunting behavior. Warblers, tits and wrens have slender, forcepslike bills fit for adroitly plucking insects from leaves and tree branches
Other species prefer aerial pursuit of flying insects. Swallows, nighthawks, and flycatchers have wide, flattened beaks for snapping down on their prey while both are in flight.
Hummingbirds, with their long tubular bills, extract nectar from flowers but are also adept at catching insects as their bills can snap shut in less than 1/100th of a second.
Bird bills, or beaks, are constructed of two components. The jaw, comprised of the bony upper and lower mandibles, is of course part of the skull. Covering the jaw is a thin, softer, more flexible material composed of keratin, a structural protein, the same material that forms your hair, nails, and skin. It grows continually as birds wear the beak down during their daily activities. This beak covering is called the rhampotheca, from the Greek for "beak sheath."
Birds have no teeth, so tearing flesh, cracking seeds, and catching fish would seem to pose a problem, but evolution has come to the rescue once again. The edges of the two mandibles are called tomia (singular, tomium). In mergansers, fish eating waterfowl, the tomia have sawtooth serrations, serving to hold the fish. Geese have smaller serrations to help cutting grass while grazing.Seed eating birds have sharp tomia with ridges to help crack seeds, although their palate helps in the process. Falcons have a tooth on their upper tomia to help tear flesh.
Many birds have hooks on the end of their bills to help with holding prey such as flycatchers, vireos, penguins, pelicans, hawks, owls, parrots, and finches.
Beaks serve to catch prey, but handling, tearing, and generally puttinlg food in a condition to swallow requires other adaptations such as those to the palate, the lining of the mouth and the tongue. We'll discuss those in future blogs.
Beaks also serve many other functions - as a tool to manipulate food and nesting material, court mates, defend territories, display,, and identify themselves. Future blogs will go into detail on these functions.